Journal ArticleDOI
An image-shearing speckle-pattern interferometer for measuring bending moments
J A Leendertz,J N Butters +1 more
TLDR
In this paper, a fringe system is obtained showing contours of constant slope resolved in the direction of image displacement, which is a comparison with result obtained by holographic interferometry.Abstract:
The surface to be studied is illuminated with laser light and two images are formed, displaced relative to one another in the image. Speckle pattern interferometry is used to measure phase changes between the two images resulting from deformation of the surface. A fringe system is obtained showing contours of constant slope resolved in the direction of image displacement. A comparison is made with result obtained by holographic interferometry.read more
Citations
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Journal ArticleDOI
The detection of aeronautical defects in situ on composite structures using Non Destructive Testing
TL;DR: A study of three nondestructive testing methods (Ultrasonic Testing, InfraRed Thermography and Speckle Shearing Interferometry, known as Shearography) was carried out on different specific types of composite specimens having a variety of defects as mentioned in this paper.
Journal ArticleDOI
Review and comparison of shearography and active thermography for nondestructive evaluation
Y.Y. Hung,Y. S. Chen,S. P. Ng,Lei Liu,Y. H. Huang,B.L. Luk,R.W.L. Ip,Chi-Man Lawrence Wu,Po Sheun Chung +8 more
TL;DR: In this paper, a comprehensive review of shearography and active thermography and their applications in nondestructive evaluation of materials is presented, and a comparison of the advantages and limitations of two techniques for non-destructive evaluation is also presented.
Journal ArticleDOI
Shearography technology and applications: a review
TL;DR: A comprehensive overview of shearography is presented, describing the principle of operation, optical configurations, image processing algorithms and applications, with a focus on more recent technological advances.
Journal ArticleDOI
Image-shearing camera for direct measurement of surface strains.
Y.Y. Hung,C. Y. Liang +1 more
TL;DR: A new image-shearing camera which focuses two laterally sheared images at the film plane and becomes a shearing interferometer, which directly measures the derivatives of the surface displacements.
Journal ArticleDOI
Shearography: An optical measurement technique and applications
Y.Y. Hung,Ho-Pui Ho +1 more
TL;DR: Shearography as discussed by the authors is a laser-based technique for full-field, non-contacting measurement of surface deformation (displacement or strain), which was developed to overcome several limitations of holography by eliminating the reference beam.
References
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Journal ArticleDOI
Interferometric displacement measurement on scattering surfaces utilizing speckle effect
TL;DR: In this article, the distribution of intensity in the resultant pattern depends on the relative phases of the component patterns, and by measuring the correlation between the resultant patterns at two different times a change of relative phase is detected.
Journal ArticleDOI
Holographic and Video Techniques Applied to Engineering Measurement
J N Butters,J A Leendertz +1 more
TL;DR: In this article, the authors present a coherent optical metrology approach based on speckle pattern interferometry with optical to electronic interfacing by means of a modified closed-circuit television arrangement.
Journal ArticleDOI
A double exposure technique for speckle pattern interferometry
J N Butters,J A Leendertz +1 more
TL;DR: When a photographic plate is doubly exposed to a laser speckle pattern and is given a small displacement, in its own plane, between exposures then it will exhibit linear fringes in its optical Fourier transform as mentioned in this paper.